- #1
- 23,168
- 10,379
That doesn't make any sense: a crater is quite literally a splash.
Nonexistant, but surface tension actually reduces splashes. A splash is a Newtonian collision of particles. Surface tension (and viscocity) just makes the collision more inelastic (try some cooking oil...).Integral said:Really? what is the surface tension of a planet?
I thought of that, but unless the splashes were very small, that's a lot of water to boil without noticing, particularly with the rebound drop.Q_Goest said:Just guessing here, but I suspect the reason the splash "disappears" has something to do with it being so close to the boiling point. The article doesn't mention the temperature the drop was at. If it were as warm as 140 F, the water would have boiled.
Paraphrased, a splash is caused by an extremely high pressure spike and propagates as a high amplitude pressure wave. If the amplitude is high enough to break surface tension and acceleration due to gravity, particles fly off the top of the propagating wave.A deformable mesh is mapped onto the surface of the fluid to model surface effects. The forces resulting from impacts to this surface are propagated to the volume model as pressure changes. As the net upward velocity of a column increases particles are spawned to model the spray from the splash. The initial positions of the particles are distributed over the area of the surface mesh that corresponds to the rising column. Initial velocities are determined by summing the velocity vectors of the fluid flowing in the pipes under the surface and the upward velocity of the column.
Again, its just a matter of the energy of the collision. Your wood table analogy doesn't work because you are using too low of an energy level collision. But water jets are, in fact, used to gouge holes - even in metal. http://www.waterjets.org/ Its just when the energy is very low compared to the integrity of the surface, you don't get a splash. Obviously, it takes a lot of energy to pulverize your table, and you only get a splash in a solid when the solid is pulverized. But you also only get a splash in water if there is enough energy to liberate small particles of water. So try dropping a BB a quarter of an inch into some water and see if it splashes...Integral said:Russ,
I will grant your analogy as soon as I see a drop of water gouge a hole in the surface of my table splashing wood fragments across the surface. The difference in density between the involve materials is enough to make them completely different phenomena.
Enough for whom? You have observed a splash and seen photos and simulations (both computer and physical) of crater formation, right? If I tell you I own a Ford car, you can't show me a picture of a Ford truck and tell me Ford doesn't make cars.Seems that experimental evidence is not enough for you.
You absolutely do. I happened to have the links available for water, but I'll need to find some for the crater.Sure a meteor striking a planet creates a form of a splash, but you certainly will not model a water droplet hitting a solid surface in the same fashion that you model a meteor impact.
We're not in disagreement that surface tension has an effect - just on how much. It may be a key factor when comparing the splash you get from dropping a BB into a barrel of water and a barrel of cooking oil, but its not a key factor when dropping a bowling ball into the same barrel.In a water droplet surface tension is a KEY factor. I did not say HOW it effects the process, just that is AN effect. Are you capable of understand that?
Huh?I would also think that another key factor will be how the liquid wets the surface it impacts.
I translated it for those not familiar with computer 3d modeling. My paraphrase is accurate. And its tough to argue against a model that uses known physics and works.As for your quote, that is nearly unintelligible. Are sure that is what it is saying? Frankly after reading that I would search for another source.
Again, its just a matter of the energy of the collision. Your wood table analogy doesn't work because you are using too low of an energy level collision.
Russ's Crater Links: No Sense in Splash is a scientific study conducted by Dr. Russel to investigate the formation of impact craters on planetary surfaces.
This study used computer simulations and laboratory experiments to model the impact cratering process. Data from previous impact events were also analyzed.
The study found that the size and shape of impact craters are influenced by various factors such as the speed and angle of impact, the composition of the target surface, and the size and density of the impactor.
By providing a comprehensive analysis of the impact cratering process, this study helps scientists better understand the formation and characteristics of impact craters on different planetary surfaces. This can also aid in the interpretation of impact events in the geological history of planets and moons.
This study can have implications in various fields such as planetary geology, astronomy, and space exploration. It can also provide valuable insights for future missions to other planetary bodies and aid in the development of impact-resistant materials for spacecrafts.